Production of 5-methyl-N-(methyl aryl)-2-pyrrolidone, 5-methyl-N-(methyl cycloalkyl)-2-pyrrolidone and 5-methyl-N-alkyl-2-pyrrolidone by reductive amination of levulinic acid esters with cyano compounds

ABSTRACT

This invention relates to a process for producing 5-methyl-N-(methyl aryl)-2-pyrrolidone, 5-methyl-N-(methyl cycloalkyl)-2-pyrrolidone and 5-methyl-N-alkyl-2-pyrrolidone by reductive amination of levulinic acid esters with aryl or alkyl cyano compounds utilizing a metal catalyst, which is optionally supported.

FIELD OF THE INVENTION

This invention relates to a process for producing 5-methyl-N-(methylaryl)-2-pyrrolidone, 5-methyl-N-(methyl cycloalkyl)-2-pyrrolidone and5-methyl-N-alkyl-2-pyrrolidone by reductive amination of levulinic acidesters with aryl or alkyl cyano compounds utilizing a metal catalyst,which is optionally supported.

BACKGROUND OF THE INVENTION

Levulinic acid is a well-known product of hexose acid hydrolysis, andcan be inexpensively obtained from cellulose feedstocks. Consequently,it is an attractive starting material in producing many useful 5-carboncompounds and their derivatives. For example, N-cyclohexyl-2-pyrrolidoneis used as a solvent or intermediate in many industrial applications,including the electronics industry (photo-resist stripping solutions),industrial cleaners, oil/gas well maintenance, and fiber dyeing.N-[2-hydroxyethyl]-2-pyrrolidone is useful in industrial cleaning,printing inks, and gasoline and oil additives. N-octyl-2-pyrrolidone isuseful, for example, in the manufacture of agricultural products, as adetergent and dispersant, in industrial and metal cleaners, in printinginks and in fiber dyeing.

U.S. Pat. No. 3,337,585 discloses a process for preparing5-methyl-1-alkyl-2-pyrrolidone utilizing levulinic acid and a primaryalkyl amine at a temperature of 50° C. to 350° C. under carbon monoxideat a pressure of 1.0 to 101 MPa. Alkyl esters may also be used as areactant with a primary amine. Additional potential primary aminesinclude alkylene diamines, aryl amines and cycloalkyl amines. Nitriles(alkyl cyano compounds) are not used. U.S. Pat. No. 3,235,562 describesa vapor phase process for producing lactams by the reductive aminationof oxo carboxylic acids or oxo carboxylic acid esters. Volatile alkyl oraryl primary amines may be used; nitriles are not used.

An efficient and low cost process for the production of aryl, alkyl andcycloalkyl pyrrolidones would be advantageous.

SUMMARY OF THE INVENTION

The present invention is a novel, one-step process for convertinglevulinic acid esters and cyano compounds to aryl, alkyl and cycloalkylpyrrolidones as set forth in greater detail below in the presence ofcatalysts. Specifically, the present invention relates to a process forpreparing 5-methyl-N-(methyl aryl)-2-pyrrolidone (III),5-methyl-N-(methyl cycloalkyl)-2-pyrrolidone (IV), or a mixture thereof,which comprises the step of contacting a levulinic acid ester (I) withan aryl cyano compound (II) in the presence of a catalyst and hydrogengas;

-   -   wherein R₁ is an aromatic group having from 6 to 30 carbons, R₂        is hydrocarbyl or substituted hydrocarbyl, C₁-C₁₈ unsubstituted        or substituted alkyl, unsubstituted or substituted alkenyl,        unsubstituted or substituted alkynyl, unsubstituted or        substituted cycloalkyl, unsubstituted or substituted cycloalkyl        containing at least one heteroatom, unsubstituted or substituted        aryl, and unsubstituted or substituted heteroaryl, and R₃ is a        fully or partially reduced derivative of R_(1,) and wherein        5-methyl-N-(methyl aryl)-2-pyrrolidone (III), 5-methyl-N-(methyl        cycloalkyl)-2-pyrrolidone (IV), or a mixture thereof, may        comprise 100% by weight of the total products formed, or wherein        additional products may be produced.

The catalyst useful in the process of the invention is selected frommetals from the group consisting of palladium, ruthenium, rhenium,rhodium, iridium, platinum, nickel, cobalt, copper, iron, osmium;compounds thereof; and combinations thereof.

The present invention also relates to a process for preparing5-methyl-N-alkyl-2-pyrrolidone (VI) which comprises the step ofcontacting a levulinic acid ester (I) with an alkyl cyano compound (V)in the presence of a catalyst and hydrogen gas;

-   -   wherein R₂ is hydrocarbyl or substituted hydrocarbyl, C₁-C₁₈        unsubstituted or substituted alkyl, unsubstituted or substituted        alkenyl, unsubstituted or substituted alkynyl, unsubstituted or        substituted cycloalkyl, unsubstituted or substituted cycloalkyl        containing at least one heteroatom, unsubstituted or substituted        aryl, and unsubstituted or substituted heteroaryl, and wherein        R₄ is an alkyl group having from 1 to 30 carbons, and wherein R₄        may be C₁-C₃₀ unsubstituted or substituted alkyl, C₁-C₃₀        unsubstituted or substituted alkenyl, C₁-C₃₀ unsubstituted or        substituted alkynyl, C₃-C₃₀ unsubstituted or substituted        cycloalkyl, or C₃-C₃₀ unsubstituted or substituted cycloalkyl        containing at least one heteroatom, and wherein        5-methyl-N-alkyl-2-pyrrolidone (VI) may comprise 100% by weight        of the total product formed, or wherein additional products may        be produced.

The catalyst useful in this process of the invention is selected frommetals from the group consisting of palladium, ruthenium, rhenium,rhodium, iridium, platinum, nickel, cobalt, copper, iron, osmium;compounds thereof; and combinations thereof.

DETAILED DESCRIPTION OF THE INVENTION

By “levulinic acid ester” is meant the compound having the followingformula, wherein R₂ is hydrocarbyl or substituted hydrocarbyl, C₁-C₁₈unsubstituted or substituted alkyl, unsubstituted or substitutedalkenyl, unsubstituted or substituted alkynyl, unsubstituted orsubstituted cycloalkyl, unsubstituted or substituted cycloalkylcontaining at least one heteroatom, unsubstituted or substituted aryl,and unsubstituted or substituted heteroaryl:

By “aryl cyano compound” is meant the compound having the formula R—CNwherein R is an aromatic group.

By “5-methyl-N-(methyl aryl)-2-pyrrolidone” is meant the compound havingthe general formula below wherein R₁ is an aryl group having from 6 to30 carbons:

By “5-methyl-N-(methyl cycloalkyl)-2-pyrrolidone is meant the compoundhaving the general formula below wherein R₃ is a cycloalkyl group havingfrom 6 to 30 carbons:

By “5-methyl-N-alkyl-2-pyrrolidone” is meant the compound having thegeneral formula below wherein R₄ is C₁-C₃₀ unsubstituted or substitutedalkyl, C₁-C₃₀ unsubstituted or substituted alkenyl, C₁-C₃₀ unsubstitutedor substituted alkynyl, C₃-C₃₀ unsubstituted or substituted cycloalkyl,or C₃-C₃₀ unsubstituted or substituted cycloalkyl containing at leastone heteroatom:

By “catalyst” is meant a substance that affects the rate of the reactionbut not the reaction equilibrium, and emerges from the processchemically unchanged.

By “metal catalyst” is meant a catalyst that is comprised of at leastone metal, at least one Raney metal, compounds thereof or combinationsthereof.

By “promoter” is meant an element of the Periodic Table that is added toenhance the physical or chemical function of the catalyst. The promotercan also be added to retard undesirable side reactions and/or affect therate of the reaction.

By “metal promoter” is meant a metallic compound that is added toenhance the physical or chemical function of a catalyst. The metalpromoter can also be added to retard undesirable side reactions and/oraffect the rate of the reaction.

By “fully or partially reduced derivative” of an aryl compound is meanta compound that can be derived from the parent compound by saturating orreducing one or more of the unsaturated bonds in the aromatic ring.Unsaturated compounds are compounds that contain one or more carbon tocarbon double or triple bonds. For example, a fully reduced derivativeof a phenyl group is a cyclohexyl group.

This invention relates to the synthesis of 5-methyl-N-(methylaryl)-2-pyrrolidone (III), 5-methyl-N-(methyl cycloalkyl)-2-pyrrolidone(IV), or a mixture thereof, from a reaction between a levulinic acidester (I) and an aryl cyano compound (II) in the presence of a catalystand hydrogen;

-   -   wherein R₁ is an aromatic group having from 6 to 30 carbons, R₂        is hydrocarbyl or substituted hydrocarbyl, C₁-C₁₈ unsubstituted        or substituted alkyl, unsubstituted or substituted alkenyl,        unsubstituted or substituted alkynyl, unsubstituted or        substituted cycloalkyl, unsubstituted or substituted cycloalkyl        containing at least one heteroatom, unsubstituted or substituted        aryl, and unsubstituted or substituted heteroaryl, and R₃ is a        fully or partially reduced derivative of R₁, and wherein        5-methyl-N-(methyl aryl)-2-pyrrolidone (III), 5-methyl-N-(methyl        cycloalkyl)-2-pyrrolidone (IV), or a mixture thereof, may        comprise 100% by weight of the total products formed, or wherein        additional products may be produced.

In addition, this invention relates to the synthesis of5-methyl-N-alkyl-2-pyrrolidone (VI) from a reaction between a levulinicacid ester (I) and an alkyl cyano (V) compound in the presence of acatalyst and hydrogen;

-   -   wherein R₂ is hydrocarbyl or substituted hydrocarbyl, C₁-C₁₈        unsubstituted or substituted alkyl, unsubstituted or substituted        alkenyl, unsubstituted or substituted alkynyl, unsubstituted or        substituted cycloalkyl, unsubstituted or substituted cycloalkyl        containing at least one heteroatom, unsubstituted or substituted        aryl, and unsubstituted or substituted heteroaryl, and wherein        R₄ is an alkyl group having from 1 to 30 carbons, and wherein R₄        may be C₁-C₃₀ unsubstituted or substituted alkyl, C₁-C₃₀        unsubstituted or substituted alkenyl, C₁-C₃₀ unsubstituted or        substituted alkynyl, C₃-C₃₀ unsubstituted or substituted        cycloalkyl, or C₃-C₃₀ C₃₀ unsubstituted or substituted        cycloalkyl containing at least one heteroatom, and wherein        5-methyl-N-alkyl-2-pyrrolidone (VI) may comprise 100% by weight        of the total product formed, or wherein additional products may        be produced.

A catalyst, with or without a support, may be present in the processesof the invention to effect the amination reactions. A promoter mayoptionally be used to aid the reactions. The promoter can be a metal.

The processes of the present invention may be carried out in batch,sequential batch (i.e., a series of batch reactors) or in continuousmode in any of the equipment customarily employed for continuous process(see for example, H. S. Fogler, Elementary Chemical ReactionEngineering, Prentice-Hall, Inc., N.J., USA). The condensate waterformed as the product of the reaction is removed by separation methodscustomarily employed for such separations, such as distillation.

The aryl and cycloalkyl groups represented by R₁ and R₃ in Formulas(II), (III) and (IV) preferably have!from 6 to 30 carbons. Morepreferably, the aryl and cycloalkyl groups represented by R₁ and R₃ inFormulas (II), (III) and (IV) have from 6 to 12 carbons. An example of apreferred embodiment of Formula (II) is benzonitrile; thus Formulas(III) and (IV) would be 5-methyl-N-benzyl-2-pyrrolidone and5-methyl-N-(methyl cyclohexyl)-2-pyrrolidone, respectively. Thehydrocarbyl or substituted hydrocarbyl group represented by R₂preferably has from 1 to 18 carbons. More preferably, R₂ has from 1 to12 carbons. The unsubstituted or substituted alkyl or cycloalkyl grouprepresented by R₄ in Formulas (V) and (VI) preferably has from 1 to 30carbons. More preferably the unsubstituted or substituted alkyl orcycloalkyl group represented by R₄ in Formulas (V) and (VI) has from 1to 12 carbons.

In the processes of the invention, a molar ratio of cyano compound tolevulinic acid ester of from about 0.01/1 to about 100/1 is preferred atthe start of the reaction. A molar ratio of cyano compound to levulinicacid ester of from about 0.10/1 to about 5/1 is further preferred at thestart of the reaction.

A temperature range of from about 25° C. to about 300° C. is preferredfor the processes of the invention. A temperature range of from about75° C. to about 225° C. is further preferred.

A pressure range of from about 0.3 MPa to about 20 MPa is employed forthe processes of the invention. A pressure range of from about 1.3 MPato about 7.6 MPa is preferred.

The reactions of the present invention can be performed in non-reactingsolvent media such as water, alcohols, ethers, and pyrrolidones.Alternatively, the excess of aryl or alkyl cyano compound can also actas the solvent medium.

The catalyst useful in the invention is a substance that affects therate of the reaction but not the reaction equilibrium, and emerges fromthe process chemically unchanged. A chemical promoter generally augmentsthe activity of a catalyst. The promoter herein may be incorporated intothe catalyst during any step in the chemical processing of the catalystconstituent. The chemical promoter generally enhances the physical orchemical function of the catalyst agent, but can also be added to retardundesirable side reactions.

The processes of the invention involve reductive amination of levulinicacid esters with aryl or alkyl cyano compounds, which is effected in thepresence of a catalyst. The principal component of the catalyst usefulherein is selected from metals from the group consisting of palladium,ruthenium, rhenium, rhodium, iridium, platinum, nickel, cobalt, copper,iron, osmium; compounds thereof; and combinations thereof.

A promoter may be used optionally in the reactions of the presentinvention. The promoter herein may be incorporated into the catalystduring any step in the chemical processing of the catalyst constituent.Suitable promoters for the processes of the invention include metalsselected from tin, zinc, copper, gold, silver, and combinations thereof.The preferred metal promoter is tin. Other promoters that can be usedare elements selected from Group 1 and Group 2 of the Periodic Table.

The catalyst used in the process may be supported or unsupported. Asupported catalyst is one in which the active catalyst agent isdeposited on a support material by a number of methods, such asspraying, soaking or physical mixing, followed by drying, calcination,and if necessary, activation through methods such as reduction oroxidation. Materials frequently used as a support are porous solids withhigh total surface areas (external and internal) which can provide highconcentrations of active sites per unit weight of catalyst. The catalystsupport may enhance the function of the catalyst agent. A supportedmetal catalyst is a supported catalyst in which the catalyst agent is ametal.

A catalyst that is not supported on a catalyst support material is anunsupported catalyst. An unsupported catalyst may be platinum black or aRaney catalyst. The term “Raney catalyst” as used herein refers tocatalysts that have a high surface area due to selectively leaching analloy containing the active metal(s) and a leachable metal (usuallyaluminum). The term Raney catalyst is not meant to denote any particularsource of the material. Raney catalysts have high activity due to thehigher specific area and allow the use of lower temperatures inhydrogenation reactions. The active metals of Raney catalysts includenickel, copper, cobalt, iron, rhodium, ruthenium, rhenium, osmium,iridium, platinum, palladium; compounds thereof; and combinationsthereof.

Promoter metals may also be added to the base Raney metals to affectselectivity and/or activity of the Raney catalyst. Promoter metals forRaney catalysts may be selected from transition metals from Groups IIIAthrough VIIIA, IB and IIB of the Periodic Table of the Elements.Examples of promoter metals include chromium, molybdenum, platinum,rhodium, ruthenium, osmium, and palladium, typically at about 2% byweight of the total metal.

The catalyst support useful herein can be any solid, inert substanceincluding, but not limited to, oxides such as silica, alumina andtitania; barium sulfate; calcium carbonate; and carbons. The catalystsupport can be in the form of powder, granules, pellets, or the like.

A preferred support material of the invention is selected from the groupconsisting of carbon, alumina, silica, silica-alumina, silica-titania,titania, titania-alumina, barium sulfate, calcium carbonate, strontiumcarbonate, compounds thereof and combinations thereof. Supported metalcatalysts can also have supporting materials made from one or morecompounds. More preferred supports are carbon, alumina, titania andsilica. Further preferred supports are carbons with a surface areagreater than 100 m²/g. A further preferred support is carbon with asurface area greater than 200 m²/g. Preferably, the carbon has an ashcontent that is less than 5% by weight of the catalyst support; the ashcontent is the inorganic residue (expressed as a percentage of theoriginal weight of the carbon) which remains after incineration of thecarbon.

Commercially available carbons which may be used in this inventioninclude those sold under the following trademarks: Bameby & Sutcliffe™,Darco™, Nuchar™, Columbia JXN™, Columbia LCK™, Calgon PCB™, Calgon BPL™,Westvaco™, Norit™ and Barnaby Cheny NB™. The carbon can also becommercially available carbon such as Calsicat C, Sibunit C, or Calgon C(commercially available under the registered trademark Centaur(R)).

In the processes of the invention, the preferred content of the metalcatalyst in the supported catalyst is from about 0.1% to about 20% ofthe supported catalyst based on metal catalyst weight plus the supportweight. A more preferred metal catalyst content range is from about 1%to about 10% of the supported catalyst. A further preferred metalcatalyst content range is from about 3% to about 7% of the supportedcatalyst.

Combinations of catalyst and support system may include any one of themetals referred to herein with any of the supports referred to herein.Preferred combinations of catalyst and support include palladium oncarbon, palladium on silica, palladium on calcium carbonate, palladiumon barium sulfate, palladium on alumina, palladium on titania, platinumon carbon, platinum on alumina, platinum on silica, iridium on silica,iridium on carbon, iridium on alumina, rhodium on carbon, rhodium onsilica, rhodium on alumina, nickel on carbon, nickel on alumina, nickelon silica, rhenium on carbon, rhenium on silica, rhenium on alumina,ruthenium on carbon, ruthenium on alumina, ruthenium on silica andcombinations thereof.

Further preferred combinations of catalyst and support include palladiumon carbon, palladium on alumina, palladium on titania, ruthenium oncarbon, ruthenium on alumina, rhodium on carbon, rhodium on alumina,platinum on carbon, platinum on alumina, iridium on silica, iridium oncarbon, iridium on alumina and combinations thereof.

The levulinic acid useful in the processes of the invention may beobtained using traditional chemical routes or obtained from biobased,renewable cellulosic feedstocks. Utilization of bio-derived levulinicacid is likely to reduce the cost of manufacture of the compounds hereinrelative to conventional methods.

The compounds produced by the processes of the current invention displayproperties that are useful in diverse applications. N-alkyl pyrrolidoneswith alkyl chains up to about 8 carbons function as aprotic chemicalsolvents with a lower toxicity profile than other solvents. The carbonchains of N-lower pyrrolidones are not long enough to allow micelleformation in water; thus these compounds do not exhibit significantsurfactant properties. N-alkyl pyrrolidones with alkyl groups of aboutC₈ to C₁₄ exhibit surfactant properties, and pyrrolidones with longerN-alkyl chains act as complexing agents. The surface active propertiesof alkyl pyrrolidones, such as solubility, wetting, viscosity building,emulsifying and complexing are described in U.S. Pat. No. 5,294,644.N-alkyl pyrrolidones can also be used for concentrating colloidalparticles. Due to their solvent, surfactant and complexing properties,pyrrolidones are very useful in the manufacture of pharmaceuticals,personal care products, and industrial, agricultural and householdchemicals and products.

The pyrrolidones produced by the processes of the invention are usefulin preparing pharmaceutical products for use on humans, animals,reptiles, and fish. The pyrrolidones disclosed herein are particularlyuseful in topical formulations, such as ointments, creams, lotions,pastes, gels, sprays, aerosols, lotions, shampoos, foams, creams, gels,ointments, salves, milks, sticks, sprays, balms, emulsions, powders,solid or liquid soaps, or oils. Pyrrolidones, such as5-methyl-2-pyrrolidones, can be used to enhance the transdermalpenetration of active components into human or animal tissues andsystems. Pyrrolidones can also act as solubilizers to enhance thesolubility of a therapeutic agent in the carrier system.

The pyrrolidones produced by the processes of the invention may also beincorporated into matrix systems, such as patches, for the transdermaladministration of, for example, an antimicrobial, a hormone, or ananti-inflammatory. The methods of preparation of pharmaceuticalcompositions as are commonly practiced in the pharmaceutical industryare useful with the processes of the invention. For discussion of suchmethods, see, for example, Remington's Pharmaceutical Sciences (A RGennaro, ed., 20^(th) Edition, 2000, Williams & Wilkins, PA)incorporated herein by reference.

The pyrrolidones made by the processes of the invention may be used assolvents or surfactants in liquid, gel or aerosol cleaning compositionsfor cleaning a wide range of surfaces, including textiles, such asclothing, fabrics and carpets, and hard surfaces, such as glass, metal,ceramics, porcelain, synthetic plastics and vitreous enamel. Thepyrrolidones may also be used in formulations for disinfecting hardsurfaces, such as in the household, or in institutional or hospitalenvironments, or the surface of skin, or fabric surfaces, or in the foodpreparation, restaurant or hotel industries. In addition, cleaningcompositions are useful for the removal of industrial soils, such asdirt, grease, oil, ink and the like. The pyrrolidones may also be usedas solvents in compositions for cleaning, solvating, and/or removingplastic resins or polymers from manufactured articles or manufacturingequipment.

In addition to pyrrolidones, other components may be included incleaning compositions. These additional components include nonionicsurfactants, anionic surfactants, cationic surfactants, amphotericsurfactants and solvents. Illustrative nonionic surfactants are alkylpolyglycosides, such as Glucopon (Henkel Corporation), ethylene oxideand mixed ethylene oxide/propylene oxide adducts of alkylphenols, theethylene oxide and mixed ethylene oxide/propylene oxide adducts of longchain alcohols or of fatty acids, mixed ethylene oxide/propylene oxideblock copolymers, esters of fatty acids and hydrophilic alcohols, suchas sorbitan monooleate, alkanolamides, and the like.

Illustrative anionic surfactants are the soaps, higher alkylbenzenesulfonates containing from 9 to 16 carbons in the higher alkyl group ina straight or branched chain, C₈-C₁₅ alkyl toluene sulfonates, C₈-C₁₅alkyl phenol sulfonates, olefin sulfonates, paraffin sulfonates, alcoholand alcoholether sulfates, phosphate esters, and the like.

Illustrative cationic surfactants include amines, amine oxides,alkylamine ethoxylates, ethylenediamine alkoxylates such as theTetronic® series from BASF Corporation, quaternary ammonium salts, andthe like.

Illustrative amphoteric surfactants are those which have both acidic andbasic groups in their structure, such as amino and carboxyl radicals oramino and sulfonic radicals, or amine oxides and the like. Suitableamphoteric surfactants include betaines, sulfobetaines, imidazolines,and the like.

Illustrative solvents include glycols, glycol ethers, aliphaticalcohols, alkanolamines, pyrrolidones and water.

Such surfactants and solvents are described, for example, inMcCutcheon's (2002), Volume 1 (Emulsifiers and Detergents) and Volume 2(Functional Materials), The Manufacturing Confectioner Publishing Co.,Glen Rock, N.J.

Cleaning compositions may also include additional components, such aschelating agents, corrosion inhibitors, antimicrobial compounds,buffering and pH adjusting agents, fragrances or perfumes, dyes, enzymesand bleaching agents.

N-alkyl-2-pyrrolidones are useful in cleaning and stripping formulationswhich are used to remove (or strip) a photoresist film (or other similarorganic polymeric material film) or layer from a substrate, or to removeor clean various types of plasma-etch residues from a substrate.N-alkyl-2-pyrrolidones are also useful as surfactants in cleaningformulations for removing solder pastes from printing applicators andcircuit assemblies.

N-alkyl-2-pyrrolidones, such as 5-methyl-N-octyl-2-pyrrolidone and5-methyl-N-dodecyl-2-pyrrolidone, may be included as components in inkjet inks in order to improve resistance to highlighter smear whenprinted into an image, lead to an even print (minimize the degree ofbanding) and impart an improved waterfast resistance and/or a better dryor wet rub property. 2-Pyrrolidones, such as5-methyl-N-cyclohexyl-2-pyrrolidone or 5-methyl-N-methyl-2-pyrrolidone,may also be used as a solvent in the preparation of hot melt or phasechange inks for color printing.

The pyrrolidones made by the processes of the invention can also beutilized in the manufacture of agrochemicals, including but not limitedto herbicides, insecticides, fungicides, bactericides, nematicides,algicides, mulluscicides, virucides, compounds inducing resistance toplants, repellants of birds, animals and insects, and plant growthregulators, or mixtures thereof. The method of manufacture comprisescontacting an agrochemically effective agent as known to persons skilledin the art with at least one of the pyrrolidones produced by any of themethods of the invention. The agrochemical composition can optionallycomprise additional auxilary components as are commonly used in theagrochemical industry.

Pyrrolidones, such as 5-methyl-N-methyl pyrrolidone and5-methyl-N-cyclohexyl pyrrolidone, can be used as water insoluble polarco-solvents to solubilize water insoluble pesticides and otheragrochemicals and increase the effective amount of active ingredient.N-alkyl pyrrolidones, preferably N-C₃₋₁₅ alkyl pyrrolidones, inparticular 5-methyl-N-octyl pyrrolidone and5-methyl-N-dodecylpyrrolidone, can be used as nonionic surfactants thataid as emulsifiers. Plant growth regulators are used to improve theeconomic yield of agricultural plants. 5-Methyl-N-octyl pyrrolidone and5-methyl-N-dodecyl pyrrolidone can be utilized as solvents in emulsionscontaining plant growth regulators.

In addition, pyrrolidones can be utilized in liquid or aerosolformulations for dermal application of insect repellants by humans;examples include mosquito and tick repellants. Manufacture of suchinsect repellants comprises contacting an effective amount of at leastone insect repelling agent with at least one product produced using atleast one process of the invention.

Pyrrolidones, such as 5-methyl-N-methyl-2-pyrrolidone, can also be usedin antimicrobial formulations for the preservation of animal silage.5-Methyl-N-alkyl-2-pyrrolidones can also be used as part of a moreenvironmentally-conscious method for dry-cleaning clothing that includesa surfactant and densified carbon dioxide in place of traditionalsolvents.

In addition, 5-methyl-2-pyrrolidones can be used as components in aprotective composition for use on painted surfaces, such as cars. Thepyrrolidones function to wet the surface and promote spreadibility ofthe protectant.

Different plastic materials are often not miscible, resulting inproducts that exhibit insufficient mechanical properties. Monomeric andpolymeric 5-methyl-pyrrolidone-containing compounds can be used ascompatibilizers for plastic compositions; the compatibilizers attachthemselves to the interface between the polymers involved, or penetrateinto the polymers, thereby improving the adhesion between the polymersand enhancing mechanical properties.

5-Methyl-N-pyrrolidones can also be used as compatibilizers in therefrigeration and air conditioning industries. Transitioning fromchlorofluorocarbon to hydrofluorocarbon refrigerants has necessitatedthe use of a new class of lubricants due to immiscibility withconventional lubricants such as mineral oil, poly α-olefin andalkylbenzene. However the new class of lubricants is expensive and alsovery hygroscopic. Absorption of water leads to acid formation andcorrosion of the refrigeration system, as well as the formation ofsludges. The lack of solubility of the hydrofluorocarbons in theconventional lubricants results in a highly viscous lubricant in thenon-compressor zones, and results in insufficient lubricant return tothe compressor. This can eventually result in a number of problems,including the compressor overheating and seizing and insufficient heattransfer in the refrigeration system. Compatibilizers solubilize thepolar halogenated hydrocarbon refrigerant and the conventional non-polarlubricant in the non-compressor zones, which results in efficient returnof lubricant to the compressor zone. Compatibilizers may include the5-methyl-N-alkyl- and 5-methyl-N-cycloalkyl-2-pyrrolidones.

Pyrrolidones can also be used as fuel and lubricant additives. Forexample, N-alkyl-2-pyrrolidones can be used as detergents anddispersants in fuel additive compositions to keep valves, carburetorsand injection systems clean, thereby improving the combustioncharacteristics and reducing deposits, thus reducing air pollutingemissions. In addition, 5-methyl-N-methyl-2-pyrrolidone can be used toremove unsaturated hydrocarbons from raw lube distillates or deasphaltedresidual lube stocks to produce solvent-refined base oils as lubricants.

Methods for the preparation of cleaning, stripping, agrochemical andplastic formulations are well known to persons skilled in the art.Similarly, methods for the preparation of insect repellents, ink jetinks, protective formulations for paint, fuel additives and lubricants,refrigeration and air conditioning lubricants, and for dry cleaning arewell known in the art. Pyrrolidones can act as solvents, surfactants,dispersants, detergents, emulsifiers, viscosity builders and complexingagents in these formulations. Appropriate pyrrolidones are selectedbased on standard screening procedures for product performance.Additional components, such as pharmaceutical or agrochemical activeagents or colorants, may be added to specific formulations as the mainfunctional component; the nature of the functional component orcomponents would be determined by the specific use. Auxiliarycomponents, which enhance or are critical to the efficacy of theformulation, may also be added. Auxiliary components may includesolvents or cosolvents, thickeners, antioxidants, spreading agents,preservatives, adhesives, emulsifiers, defoamers, humectants,dispersants, surfactants, suitable carriers, matrix systems, deliveryvehicles, fragrances, salts, esters, amides, alcohols, ethers, ketones,acids, bases, alkanes, silicone, evaporation modifiers, paraffins,aliphatic or aromatic hydrocarbons, chelating agents, gases foraerosols, propellants or for dry cleaning, oils and water. Appropriateauxiliary components for the uses described herein are known to personsskilled in the art.

The following examples are illustrative of the invention. Examples 1 to56 are actual examples; Examples 57 to 62 are prophetic.

EXAMPLES

The following abbreviations are used: ESCAT-XXX: Series of catalystsprovided by Engelhard Corp. (Iselin, NJ) JM-AXXXX, Series of catalystsfrom Johnson Matthey, JM-XXXX: Inc. (W. Deptford, NJ) Calsicat Carbon:Catalyst support from Engelhard Corp. Sibunit Carbon: Catalyst supportfrom Inst. of Technical Carbon, Omsk, Russia Calgon Carbon: Catalystsupport from Calgon Carbon Corp. under the brand name of Centaur(R)(Pittsburgh, PA) ST-XXXX-SA: Series of catalysts from Strem Chemicals(Newburyport, MA) SCCM: Standard cubic centimeters per minute GC: Gaschromatography GC-MS: Gas chromatography-mass spectrometry

For catalyst preparation a commercially available support such ascarbon, alumina, silica, silica-alumina or titania was impregnated byincipient wetness with a metal salt. The catalyst precursors used wereNiCl₂.6H₂O (Alfa Chemical Co., Ward Hill, Mass.), Re₂O₇ (Alfa ChemicalCo.), PdCl₂ (Alfa Chemical Co.), IrCl₃.3H₂O (Alfa Chemical Co.),RuCl₃.xH₂O (Aldrich Chemical Co., Milwaukee, Wis.), H₂PtCl₆ (JohnsonMatthey, Inc.), and RhCl₃.xH₂O (Alfa Chemical Co.). The samples weredried and reduced at 300-450° C. under H₂ for 2 hours.

The carbon used was commercially available as Calsicat Carbon, SibunitCarbon, or Calgon Carbon (commercially available under the registeredtrademark Centaur®). Calsicat Carbon is lot S-96-140 from EngelhardCorp. Sibunit Carbon is Sibunit-2 from Institute of Technical Carbon,5th Kordnaya, Omsk 64418, Russia. Calgon Carbon is PCB Carbon fromCalgon Corp. (commercially available under the registered trademark ofCentaur(R)). Raney catalysts are available from W.R. Grace & Co.(Columbia, Md.), and pentenenitrile, benzonitrile, adiponitrile,propionitrile, dioxane and ethyl levulinate are available from FisherScientific (Chicago, Ill.).

Catalyst Preparation: 5% Pt on Acid Washed Calsicat Carbon

In a 150 ml beaker, a solution was made up of 4.5 ml 0.3 M H₂PtCl₆ with4.0 ml deionized H₂O. To the beaker were added 4.75 g Calsicat AcidWashed Carbon (12×20 mesh, dried at 120° C. overnight). The slurry wasallowed to stand at room temperature for 1 hr with occasional stirring,followed by drying at 120° C. overnight with frequent stirring (untilfree flowing).

In an alumina boat, in a quartz lined tube furnace, the catalyst waspurged with 500 SCCM N₂ at room temperature for 15 min and then with 100SCCM He at room temperature for 15 min. The catalyst was heated to 150°C. and held at 150° C. under He for 1 hr. At this point, 100 SCCM H₂were added and the sample was held at 150° C. under He and H₂ for 1 hr.The temperature was increased to 300° C. and the catalyst was reduced at300° C. under He—H₂ for 8 hrs. The H₂ was stopped, the sample was heldat 300° C. under He for 30 min and then cooled to room temperature inflowing He. The catalyst was finally passivated in 1.5% O₂ in N₂ at 500SCCM,for 1 hr at room temperature and weighed 4.93 g when unloaded.

Additional catalysts used in the present invention were preparedfollowing a similar procedure.

Batch Reduction of Ethyl Levulinate to 5-Methyl-N-(MethylAryl)-2-Pyrrolidone and 5-Methyl-N-(Methyl Cycloalkyl)-2-Pyrrolidone

To a 5 ml pressure vessel was added 50 gm of catalyst, and 1 gm of asolution containing 30 wt % ethyl levulinate, 22% aryl cyano compoundand 48% dioxane. The vessel was sealed, charged with 5.52 MPa hydrogenand heated to 150° C. for 4 hours. The pressure was maintained at 5.52MPa during the course of the reaction. At the end of the reaction, thevessel was rapidly cooled in ice, vented and an internal GC standard ofmethoxyethylether was added. The solution was separated by pipette thecatalyst and analyzed by GC-MS using an HP 6890 (Agilent; Palo Alto,Calif.) equipped with a FFAP 7717 (30 meter) column. The results setforth in the tables below are based on area %.

The examples described below were performed according to a similarprocedure under the conditions indicated.

Examples 1-12 Preparation of Hexane-1,6-(5-Methyl-2-Pyrrolidone) (HDMP)by Batch Reduction of Ethyl Levulinate (EL) Using Adiponitrile (ADPN) asthe Alkyl Cyano Compound

The reactions were carried out for 4 hours at a temperature and pressureof 150° C. and 5.52 MPa, respectively. The feedstock was ethyllevulinate/adiponitrile/dioxane at a ratio (wt. %) of 40/15/45. Theresults are set forth in the following table. HDMP EL (dimer) Ex.Conversion Selectivity No. Catalyst/Support^(a) (%) (%) 1 5% Pd/C(ESCAT-142) 38.3 1.8 2 5% Pt/C (ESCAT-248) 48.0 3.2 3 5% Rh/C (JM-11761)54.1 3.1 4 5% Ru/C (ESCAT-440) 92.2 21.7 5 5% Re/C (Fisher) 8.8 0.0 6 5%Ir/Calsicat C 84.9 10.5 7 5% Pd/Al₂O₃ (ESCAT-124) 53.8 9.1 8 5% Pt/Al₂O₃(ESCAT-294) 67.4 12.9 9 5% Rh/Al₂O₃ (Fisher) 62.7 4.3 10 5% Ru/Al₂O₃(ESCAT-44) 85.5 20.1 11 5% Re/Al₂O₃ 6.1 0.0 12 5% Ir/Al₂O₃ 84.1 19.0^(a)Source for commercially available catalyst/support is inparentheses.

Examples 13-30 Preparation of 5-Methyl-N-Propyl-2-Pyrrolidone (PrMP) and5-Methyl-2-Pyrrolidone (MP) by Batch Reduction of Ethyl Levulinate (EL)Using Propionitrile (PN) as the Alkyl Cyano Compound

The reactions were carried out for 4 hours at a temperature and pressureof 150° C. and 5.52 MPa, respectively. The feedstock was ethyllevulinate/propionitrile/dioxane at a ratio (wt. %) of 30/15/55. Theresults are set forth in the following table. EL PrMP MP Ex. ConversionSelectivity Selectivity No. Catalyst/Support^(a) (%) (%) (%) 13 5% Pd/C(ESCAT-142) 59.6 55.6 30.3 14 5% Pt/C (ESCAT-248) 51.6 43.3 32.9 15 5%Ru/C (ST-141060-SA) 84.9 30.6 32.6 16 5% Rh/C (JM-11761) 73.3 40.9 53.417 5% Re/C (Fisher) 3.1 42.6 27.4 18 5% Ir/Calsicat C 93.9 48.0 19.6 195% Pd/Al₂O₃ 92.9 42.5 51.2 20 5% Pt/Al₂O₃ (ESCAT- 77.9 47.4 49.2 294) 215% Ru/Al₂O₃ (ESCAT- 88.5 58.0 30.4 44) 22 5% Rh/Al₂O₃ (Fisher) 71.6 35.162.4 23 5% Re/Al₂O₃ 1.6 16.7 21.6 24 5% Ir/Al₂O₃ 95.7 54.1 29.6 25 5%Pd/SiO₂ 89.8 50.5 40.1 26 5% Pt/SiO₂ 79.2 40.2 53.0 27 5% Ru/SiO₂ 92.251.0 27.0 28 5% Rh/SiO₂ 82.9 41.7 50.3 29 5% Re/SiO₂ 3.7 42.6 11.7 30 5%Ir/SiO₂ 96.9 64.0 25.2^(a)Source for commercially available catalyst/support is inparentheses.

Examples 31-48 Preparation of 5-Methyl-N-(Methyl Phenyl)-2-Pyrrolidone(PMP) and 5-Methyl-N-(Methyl Cyclohexyl)-2-Pyrrolidone (CHMMP) by BatchReduction of Ethyl Levulinate (EL) Using Benzonitrile (BN) as the ArylCyano Compound

The reactions were carried out for 4 hours at a temperature and pressureof 150° C. and 5.52 MPa, respectively. The feedstock was ethyllevulinate/benzonitrile/dioxane at a ratio (wt. %) of 30/22/48. Theresults are set forth in the following table. EL PMP CHMMP Ex.Conversion Selectivity Selectivity No. Catalyst/Support^(a) (%) (%) (%)31 5% Pd/C (ESCAT-142) 99.8 7.2 3.2 32 5% Pt/C (ESCAT-248) 89.6 55.7 0.133 5% Ru/C (ST-141060-SA) 97.9 12.0 7.3 34 5% Rh/C (JM-11761) 99.8 43.16.7 35 5% Re/C (Fisher) 3.3 36.6 3.0 36 5% Ir/Calsicat C 96.9 61.1 1.537 5% Pd/Al₂O₃ (JM-A22117- 99.9 20.7 0.8 5) 38 5% Pt/Al₂O₃ (ESCAT-294)93.8 59.6 0.4 39 5% Ru/Al₂O₃ (ESCAT-44) 92.0 18.2 45.4 40 5% Rh/Al₂O₃(Fisher) 70.2 48.9 0.9 41 5% Re/Al₂O₃ 1.2 19.1 3.3 42 5% Ir/Al₂O₃ 95.866.3 0.7 43 5% Pd/SiO₂ 99.9 35.5 1.1 44 5% Pt/SiO₂ 95.9 64.3 0.6 45 5%Ru/SiO₂ 99.1 10.1 5.6 46 5% Rh/SiO₂ 99.6 36.0 8.4 47 5% Re/SiO₂ 1.8 23.25.8 48 5% Ir/SiO₂ 97.9 68.6 3.1^(a)Source for commercially available catalyst/support is inparentheses.

Examples 49-56 Preparation of 5-Methyl-N-Pentyl-2-Pyrrolidone (PeMP) byBatch Reduction of Ethyl Levulinate (EL) Using 3-Pentenenitrile (3PN) asthe Alkyl Cyano Compound

The reactions were carried out at 150° C. The results are set forth inthe following table. Abbreviation: Con, Conversion; Sel, Selectivity. H₂Feedstock PeMP Catalyst/ Time Pressure Ratio EL Con Sel Ex. No.Support^(a) (hrs) (MPa) Feedstock (wt %) (%) (%) 49 5% Rh/Sibunit C 45.52 EL/3PN/ 35/20/45 73.2 65.9 Dioxane 50 5% Rh/Calsicat C 4 5.52EL/3PN/ 35/20/45 81.9 57.4 Dioxane 51 5% Rh/Calgon C 4 5.52 EL/3PN/35/20/45 75.4 59.8 Dioxane 52 5% Rh/Al₂O₃ 4 5.52 EL/3PN/ 35/20/45 77.961.0 Dioxane 53 5% Rh/SiO₂ 4 5.52 EL/3PN/ 35/20/45 80.6 67.4 Dioxane 545% Rh/C (JM- 12 6.90 EL/3PN 64/36 91.7 20.2 11761) 55 5% Pd/C 12 6.90EL/3PN 64/36 11.6 62.9 (ESCAT-142) 56 5% Ru/C (ST- 12 6.90 EL/3PN 64/3688.4 68.1 141060-SA)^(a)Source for commercially available catalyst/support is inparentheses.

Example 57 Pharmaceutical Formulations

A) Topical Formulation: Solubilizer (diethylene glycol monoethyl ether) 2% to 50% Skin permeation enhancer  2% to 50%(N-hydroxyethyl-2-pyrrolidone) Emulsifier  2% to 20% Emollient(propylene glycol)  2% to 20% Preservative  0.01 to 0.2% Active agent   0 to 25% Carrier Balance B) Cream: Phase 1: Polyethylene glycol andethylene glycol   5% palmitostearate Caprilic/capric triglycerides   5%Oleoyl macrogolglycerides (Labrafil M 1944CS)   4% Cetyl alcohol  5.5%PPG-2 myristyl ether propionate (Crodamol PMP)   6%5-methyl-N-hydroxyethyl-2-pyrrolidone   2% Phase 2: Xanthan gum  0.3%Purified water   55% Phase 3: Propylene glycol   1% Methylparaben 0.18%Propylparaben 0.02% Phase 4: Naftifine hydrochloride (antifungal)   1%Diethylene glycol monoethyl ether (Transcutol)   15% Procedure: Xanthangum is dispersed in water and allowed to stand. Phase 1 components andphase 2 components are separately heated to 75° C.; phase 1 is mixedinto phase 2 under high speed agitation. The temperature is maintainedat 75° C. while stirring for 10 min. The mixture is then slowly cooledwhile stirring at low speed. At 40° C., phase 3 is added. Naftifine isthen mixed well into the Transcutol, and the mixture is added to thecream, mixed well and the cream is cooled to room temperature. C)Transdermal Patch Formulation: Ketoprofen  0.3% Polysorbate 80  0.5%5-Methyl-N-methyl-2-pyrrolidone   1% 5-Methyl-N-ethyl-2-pyrrolidone   2%PEG 400   10% CMC-Na   4% Na-polyacrylate  5.5% Sanwet 1M-1000PS  0.5%Polyvinyl alcohol   1% PVP/NA copolymer   3%

Example 58 Cleaning Compositions

A) Grease Removal Formulation: Water   89% Potassium carbonate    1%Potassium bicarbonate    5% 5-Methyl-N-octyl-2-pyrrolidone  2.5%Deriphatec 151-C (Henkel Corp.)  2.5% B) Oil-in-Water Emulsion inAerosol Form: Crillet 45 (Croda)  3.30% Monamulse DL 1273 (MonaIndustries, Inc.)  3.30% 5-Methyl-N-dodecyl-2-pyrrolidone  5.50%Denatured absolute ethanol 100 AG/F3 (CSR Ltd.) 15.40% Norpar 15 (Exxon) 5.50% Deionized water 44.10% Butane 16.95% Propane  5.95% C)All-Purpose Liquid Cleaning Composition: Neodol 91-8 (Shell)  3.5%Linear alkyl (C9-13) benzene sulfonate, Mg salt  10.5% Propylene glycolmono-t-butyl ether  4.0% Coco fatty acid  1.4%5-Methyl-N-decyl-2-pyrrolidone  1.0% Magnesium sulfate heptahydrate 5.0% Water  74.6 D) Shower-Rinsing Composition: Glucopon 225 (HenkelCorp.)  2.0% Isopropyl alcohol  2.2% Sequestrene 40 (45%, Ciba)  1.0%Fragrance  0.02% Barquat 4250Z (50%, Lonza)  0.2%5-Methyl-N-octyl-2-pyrrolidone  1.0% Water 93.58% E) DishwashingComposition: Ethanol (95%)  8.6% Alfonic 1412-A [Ethylene oxide sulfate(59.3%)]  22.5% Alfonic 1412-10  1.1% Sodium chloride  0.9%5-Methyl-N-decyl-2-pyrrolidone  7.5% Water  59.4% F) AqueousAntimicrobial Cleaning Composition: Adipic acid  0.40% Dacpon 27-23 AL(Condea; C₁₂₋₁₄ sodium alkyl  0.15% sulfate, 28% active) Isopropylalcohol  1.8% Dowanol PnB (Dow; propylene glycol  0.30% mono-N-butylether) 5-Methyl-N-octyl-2-pyrrolidone  0.4% Sodium hydroxide  0.05%Water  96.9% An antimicrobial wipe can be made by impregnating asubstrate with the above composition; the substrate can be spunlacecomprising viscose/ polyester at a ratio of 70:30 with a specific weightof 50 grams/m². The composition to substrate ratio is about 2.6:1. G)Disinfectant: Benzalkonium chloride    5% Sodium carbonate    2% Sodiumcitrate  1.5% Nonoxynol 10  2.5% 5-Methyl-N-octyl-2-pyrrolidone    5%Water   84% H) Anti-Parasitidal Agent (for dermal application toanimals): Antiparasital agent 1 to 20%5-Methyl-N-isopropyl-2-pyrrolidone   30% Benzyl alcohol (preservative)   3% Thickener 0.025-10% Colorant 0.025-10% Emulsifier 0.025-10% WaterBalance

Example 59 Stripping/Cleaning Formulation

5-Methyl-N-methyl-2-pyrrolidone 30% Monoethanolamine 55% Lactic acid 5%Water 10%

Example 60 Ink Jet Ink

CAB-O-JET 300 (Active)   4% Diethylene glycol 17.5%5-Methyl-N-octyl-2-pyrrolidone  2.5% Deionized H₂O   76%

Example 61 Agrochemical Compositions

A) Composition for the Control of Insects: Permethrin   2%5-Methyl-N-decyl-2-pyrrolidone   3% Dimethyl dipropyl naphthalene   7%Lauryl alcohol   5% Hymal 1071 (MatsumotoYushi Seiyaky, Inc.)  10%Hytenol N-08 (Daiichi Kogyo Seiyaku, Inc.)   2% Polyoxyethylene glycol 71% B) Pesticide Formulation: 5-Methyl-N-alkyl pyrrolidone  48% Sodiumdodecyl sulfate  12% Agrimer AL25  10% Rodeo (pesticide; Monsanto)   1%Water  29% C) Emulsifiable Fungicide Formulation: Kresoxin-methyl 0.5%Propylene carbonate 1.5% Aromatic petroleum distillate 150 (Exxon) 2.9%5-methyl-N-octyl-2-pyrrolidone 3.8% CaH/DDBSA [50% (Ca dodecylbenzene1.4% Sulfonate + Dodecylbenzene Sulfonic acid (5:1) in Exxon 150 WaterBalance

Example 62 Formulation for Protective Composition for Painted AutomobileSurfaces

Propylene glycol phenyl ether 2.0% 5-Methyl-N-octyl-2-pyrrolidone 0.1%Emulsified silicone: 3.0% a) dimethyl silicone (2.67%) b)amino-functional silicone (0.21%) c) silicone resin (0.12%) Water 94.9% 

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 18. A process for preparing anagrochemical composition, the process comprising the steps of: i)preparing 5-methyl-N-alkyl-2-pyrrolidone (VI) using a process comprisingthe step of contacting a levulinic acid ester (I) with an alkyl cyanocompound (V) in the presence of hydrogen gas and a metal catalyst, themetal catalyst being optionally supported, and, optionally, in thepresence of a solvent;

wherein R₂ is hydrocarbyl or substituted hydrocarbyl, C₁-C₁₈unsubstituted or substituted alkyl, unsubstituted or substitutedalkenyl, unsubstituted or substituted alkynyl, unsubstituted orsubstituted cycloalkyl, unsubstituted or substituted cycloalkylcontaining at least one heteroatom, unsubstituted or substituted aryl,and unsubstituted or substituted heteroaryl, and wherein R₄ is an alkylgroup having from 1 to 30 carbons, and wherein R₄ may be C₁-C₃₀unsubstituted or substituted alkyl, C₁-C₃₀ unsubstituted or substitutedalkenyl, C₁-C₃₀ unsubstituted or substituted alkynyl, C₃-C₃₀unsubstituted or substituted cycloalkyl, or C₃-C₃₀ unsubstituted orsubstituted cycloalkyl containing at least one heteroatom; and ii)contacting 5-methyl-N-alkyl-2-pyrrolidone (VI) with at least oneagrochemically effective agent.
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